Find the measure of ∠. Show your work.

m/angle ABC=47^o

Step-by-step explanation:

we know that

The measure of the external angle is the semi-difference of the arches it covers

so

m/angle ABC=/frac{1}{2}[arc / DE-arc / AC]

substitute the given values

m/angle ABC=/frac{1}{2}[142^o-48^o]

m/angle ABC=47^o